Page 1 of 29

Journal for Studies in Management and Planning

Available at

http://edupediapublications.org/journals/index.php/JSMaP/

e-ISSN: 2395-0463

Volume 02 Issue 8

August 2016

Available online: http://edupediapublications.org/journals/index.php/JSMaP/ P a g e | 465

Econometric Models to Water Use Estimation in Power

Plants: An Experiential Analysis

Perini Praveena Sri

Department of Social Science, Faculty of Economics Ethiopia, Aksum University

E-Mail: sriveena.perini@gmail.com

ABSTRACT

The purpose of this paper is to examine

water use estimation in hydel and thermal

electric power plants in selected regions

i.e. Coastal, Rayalaseema and Telangana

regions of Andhra Pradesh. The study

primarily focuses on the realistic

fundamental premise that thermal electric

and hydro electric energy generation is

responsible for the largest monthly volume

of water withdrawals in four seasons (i.e.

summer, rainy, winter and post monsoon

season) of a year. These enormous water

withdrawals by these hydel and thermal

power plants can have significant

influence on local surface water resources.

However there are very few studies of

determinants of water use in hydel and

thermal electric generation. Analysis of

hydel and thermal electric water use data

in the existing power plants clearly

indicates that there is wide variability in

unitary hydel and thermal electric water

use within the system. The multivariate

regression procedures were used to

identify the significant determinants of

thermal and hydel water withdrawals in

various power plants i.e. five hydel and

four thermal power plants. The estimated

regression coefficients indicate that the

best explanatory variables for the total

quantity of hydel water withdrawals are

storage capacity, tail water level and

actual generation and thermal water

withdrawals are condenser cooling and

ash disposal. The unit variability of unit

water usage indicates that there is

significant potential for water

conservation in existing power plants.

Keywords:

Thermal water withdrawals, hydel water

withdrawals, storage capacity, tail water

level, actual generation, condenser cooling

and ash disposal.

1.0 INTRODUCTION

Water has become a growing source of

tension especially in power sector in many

parts of the World. For India hydro and

thermal power projects are vital to fill in

the serious electric energy shortfalls that

crimp its economy. About 40 percent of

India’s population is off the power grid

and due to this the welfare of the economy

was badly affected. The main stumbling

block for this kind of worse situation are a

genuine water shortage problem in India

and the country’s inability to properly

manage large quantities of water during

rainy season has made matters worse,

exposing it to any small variation in

rainfall or river flow. Though the country

has invested heavily on nuclear power to

generate 30,000 MW and $ 19 billion to

produce factories of major thermal, hydro

and nuclear power stations, the electric

energy shortages were very much

prevalent in most parts of the country. For

this the first and foremost thing is to

judiciously manage the vital resource

“water”. The country also planned for

setting up of 20,000 MW solar power by

2020. The Government of India has an

ambitious mission of Power for All By

2012. This would require an installed

generation capacity of atleast 20,000 MW

by 2012 from the present level of

144,564.97 MU. However the power

requirement will double by 2020 to

Page 2 of 29

Journal for Studies in Management and Planning

Available at

http://edupediapublications.org/journals/index.php/JSMaP/

e-ISSN: 2395-0463

Volume 02 Issue 8

August 2016

Available online: http://edupediapublications.org/journals/index.php/JSMaP/ P a g e | 466

400,000 MW. How India is able to meet

this target with the on-going water

shortage plight in Electricity Generation

Industry is a matter of great concern.

However the Electricity Generation

Industry strategy should primarily focus on

this invisible culprit “Water” causing huge

generation losses through better water

efficiency techniques and lay emphasis on

technology up gradation and massive

utilization of renewable sources of energy.

The purpose of this paper was to examine

water use estimation at hydel and thermal

electric power plants in selected regions

i.e. Coastal, Rayalaseema and Telangana

regions of Andhra Pradesh. The study

primarily focuses on the realistic

fundamental premise that thermal electric

and hydro electric energy generation is

responsible for the largest monthly volume

of water withdrawals in four seasons (i.e.

summer, rainy, winter and post monsoon

season) of a year. These enormous water

withdrawals by these hydel and thermal

power plants can have significant

influence on local surface water resources.

Water use at the power station level (by

fuel type) can be estimated indirectly by

using multiple regression analysis. In

regression models, water use relationships

are expressed in the form of mathematical

equations, showing water use as a

mathematical function of one or more

independent (explanatory) variables. The

mathematical form (eg. Linear,

multiplicative and exponential) and the

selection of the Right hand side (RHS) or

independent variables depend on the

category and on aggregation of water

demand represented by Left Hand side

(LHS) or dependent variable.

2.0 THEORETICAL AND

CONCEPTUAL REVIEW OF

LITERATURE: DIFFERENT

APPROACHES OF WATER USE

ESTIMATION

The various studies relating to water

demand for thermal power plants and its

significant determinants are reviewed for

explicit understanding of thermal electric

energy water use. Cootner, Paul and

George O Golf (1965) have build upon a

systematic model for estimating water

demand in conventional steam electric

utility industry. They have regarded water

as a common factor input along with fuel.

Here

TWD= f (Qf, Cw, EHe, CWH )

Where in TWD = Thermal water

withdrawal demand, Qf = Quantity and

cost of fuel, Cw = Cost of water, EHe =

Economics of heat exchange and recycle

and CWH= other costs of thermal power

plant associated with the disposal of waste

heat.

In other words the quantity of the fresh

water withdrawals depends upon the above

mentioned factors. In another study

Wollman and Bonem (1971) found that the

quantity of fresh water withdrawals for

steam electric power generation depends

upon (1) Thermal efficiency (with higher

thermal efficiency less heat will be

dissipated. Due to this smaller amount of

cooling water are needed) (2) The extent to

which sea or brackish water can substitute

for fresh water (3) The rate of

recirculation. Recirculation is a function of

price of water availability. Young and

Thompson (1973) in their study identified

three factors that affect water use in

thermal electric energy generation. They

can be listed as water pricing, change in

generation, technology, price of electricity,

price of substitutes used in electricity i.e.

oil and gas, population and level of general

economic activity. The other factors

include waste and heat discharge to water

and the changes in cooling technologies.

Gleick (1993) in his study reviewed the

water requirement of electric energy.

Page 3 of 29

Journal for Studies in Management and Planning

Available at

http://edupediapublications.org/journals/index.php/JSMaP/

e-ISSN: 2395-0463

Volume 02 Issue 8

August 2016

Available online: http://edupediapublications.org/journals/index.php/JSMaP/ P a g e | 467

Taking as base of earlier studies, he

estimated the consumptive water use in

Electricity Generation Industry using

different technologies. The system

efficiency for conventional coal

combustion (Once through Cooling

Towers), natural gas combustion (Once

Through Cooling Towers) and nuclear

generation (CTs) stood at 35 percent, 36

percent and 40 percent. The estimates

specifies that with the help of Once

Through Cooling Technologies, the

average consumptive use ranges from 1.2

m3

/MWH in case of conventional coal, for

oil and natural gas consumption the

average consumption use is less by 1.1

m3

/MWH , where as with cooling towers

it was 2.6 m3

/MWH. For nuclear power

generation the average consumptive use of

water with the aid of CTs was more that

stood at 3.2 m3/MWH. There is a need for

use of high efficient technology in cooling

towers for water conservation. Electric

Power Research Institute 2002, estimated

the evaporation water loss from

recirculating towers i.e., roughly 480

gal/MWH for a coal fired power plant.

Mortenson, 2006 in his study have

provided a technological breakthrough i.e.

small scale tests of one technology (that

uses cross-currents of ambient air for

condensation) as a counteracting measure

for these evaporation losses. By this

technology the evaporation losses can be

reduced to about 60-140 gallons/MWH

(that can be applied even to hotter

climates). In value terms, EPRI 2004

notified that the savings from reduction of

evaporation losses will be $870,000.

There are very few studies of determinants

of water use in hydel and thermal electric

generation. The literature available relating

to water use estimations is very few. Water

use experts have to opt for estimation

methods for many of the water

withdrawals classes i.e. domestic,

agriculture and industry because of the true

fact that many legal, financial and political

constraints limit for getting the hard data.

For instance water withdrawals in

domestic and live stock water use are

usually estimated by multiplying

population figures by coefficient. In case

of agricultural sector, the irrigation water

withdrawals are often estimated by

multiplying the acreage by assumed water

requirements of the crop rather than by

measuring actual water pumped and

applied.

Snavely (1986), explicitly details the water

use data collection programs and

maintaining regional data base of the Great

Lakes St. Lawrence River Basin States.

The results are very much appealing

indicating as how broad the range of

estimation coefficient for water use can be

within a geographic area with similar

water availability. Mostly the estimated

coefficients used for agriculture and

domestic use vary by a factor of 10. The

econometric studies relating to water use

estimation in public supply use and thermo

electric power use have the potential to

explain temporal and geographic

variability across USA. The aggregated

water use estimates were provided by the

National water Use Information

Programme. These estimates primarily

focus on measuring total water

withdrawals (that includes annual

extraction of fresh surface water and

ground water) for the period 1980-1985 to

1990-1995 in each of 48 states of USA for

public supply water withdrawals ,

domestic, commercial, irrigation and live

stock. The saline water withdrawals were

estimated for industrial, mining and

thermal electric categories. The public

supply water withdrawals are estimated

within geographical area i during year t

using a set of explanatory variables that

includes air temperature, precipitation,

price of water, median household income

and others.